The type II cytokeratins consist of basic or neutral proteins which are arranged in pairs of heterotypic keratin chains coexpressed during differentiation of simple and stratified epithelial tissues. This type II cytokeratin is specifically expressed in the spinous and granular layers of the epidermis with family member KRT10 and mutations in these genes have been associated with bullous congenital ichthyosiform erythroderma. The type II cytokeratins are clustered in a region of chromosome 12q12-q13.Keratin 1 is specifically expressed in the spinous and granular layers of the epidermis with family member keratin 10. Mutations in this gene have been associated with the variants of bullous congenital ichthyosiform erythroderma in which the palms and soles of the feet are affected.